可以供MFC调用的，QT实现的DLL（使用qt-solutions的qtwinmigrate实现）

MFC和QT的消息循环机制不同，所以，要让QT写的DLL可以供MFC调用，要做一点特殊的处理

#include <qmfcapp.h>
#include <qwinwidget.h>
#include <QtGui>

#include <QtGui/QMessageBox>
#include <windows.h>
#include <QTextCodec>

#include "widget.h"

BOOL WINAPI DllMain( HINSTANCE hInstance, DWORD dwReason, LPVOID /*lpvReserved*/ )
{
    static bool ownApplication = FALSE;
    //加入本地语言支持
    QTextCodec::setCodecForTr(QTextCodec::codecForLocale());
    QTextCodec::setCodecForCStrings(QTextCodec::codecForLocale());

    if ( dwReason == DLL_PROCESS_ATTACH )
    {

        ownApplication = QMfcApp::pluginInstance( hInstance );
    }
    if ( dwReason == DLL_PROCESS_DETACH && ownApplication )
    {
        qApp->quit();
        delete qApp;
    }

    return TRUE;
}


extern "C" __declspec(dllexport) int ShowDialog( HWND parent)
{
    QWinWidget win(parent, NULL, Qt::Window);
    win.showCentered();
    win.center();

    QHBoxLayout hbox(&win);
    Widget *widget = new Widget(&win);
    widget->setWindowFlags(Qt::Window);
    hbox.addWidget(widget);

    win.show();
    qApp->exec();
}